ML17325A679

LER 88-003-00:on 880311,discovered That Setpoints of Voltage Relays Outside Tech Spec Allowable Values.Tech Spec Change Request Will Be Submitted as Soon as Engineering Review to Evaluate Acceptable Tech Spec Values & Tolerance Completed

ML17325A679
Person / Time
Site:	Cook
Issue date:	04/11/1988
From:	Beilman T, Will Smith INDIANA MICHIGAN POWER CO. (FORMERLY INDIANA & MICHIG
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
LER-88-003, LER-88-3, NUDOCS 8804210251
Download: ML17325A679 (7)

Text

'ACCELERATED DIFQIBUTION DEMONSTRATION SYSTEM

~ REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)

ACCESSION NBR:8804210251 DOC.DATE: 88/04/11 NOTARIZED: NO DOCKET FACIL:50-316 Donald C. Cook Nuclear Power Plant, Unit 2, Indiana & 05000316 AUTH. NAME AUTHOR AFFILIATION BEILMAN,T.P. Indiana Michigan Power Co. (formerly Indiana & Michigan Ele SMITH,W.G. Indiana Michigan Power Co. (formerly Indiana & Michigan Ele RECIP.NAME RECIPIENT AFFILIATION

SUBJECT:

LER 88-003-00:on 880311,repetitive violation of ESF instrumentation limiting conditions noted.

W/8 DISTRIBUTION CODE: IE22D COPIES RECEIVED:LTR ENCL SIZE:

TITLE: 50.73 Licensee Event Report (LER), Incident Rpt, etc.

NOTES RECIPIENT COPIES RECIPIENT COPIES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL PD3-3 LA 1 1 ~ PD3-3 PD 1 1 A STANG,J 1 1 INTERNAL: ACRS MICHELSON 1 ACRS MOELLER 2 2 AEOD/DOA 1 AEOD/DSP/NAS 1 1 AEOD/DS P/ROAB 2 AEOD/DSP/TPAB 1 1 ARM/DCTS/DAB 1 DEDRO 1 1 NRR/DE ST/ADS 7E 0 NRR/DEST/CEB 8H . 1 1 NRR/DEST/ESB 8D 1 NRR/DEST/ICSB 7 - 1 1 NRR/DEST/MEB 9H 1 NRR/DEST/MTB 9H 1 1 NRR/DEST/PSB 8D 1 NRR/DEST/RSB 8E 1 1 NRR/DEST/SGB 8D 1 NRR/DLPQ/HFB 10 1 1 NRR/DLPQ/QAB 10 1 NRR/DOEA/EAB 11 1 1 NRR/DREP/RAB 10 1 NRR/DREP/RPB 10 2 2 1 NRR/PMAS/ILRB12 1 1 1 RES TELFORD,J 1 ~ 1 S/BP/EXS 1 RES/DRPS DIR 1 1 RGN3 FILE 01 1 EXTERNAL: EG&G GROH,M FORD BLDG HOY,A 1 1 H ST LOBBY WARD LPDR 1 1 NRC PDR NSIC HARRIS,J 1 1 NSIC MAYS,G S

A D

TOTAL NUMBER OF COPIES REQUI'RED:.LTTR 45 ENCL 44

NRC Form 355 UA. NUCL'EAR REOULATORY COMMISSION (003)

APPROVED OMS NO. 3(50010l LICENSEE EVENT REPORT HLER) EXPIRES: BISIISB FACILITY NAME (II DOCKKT NUMSKR (2) PA E D. C. COOK NUCLEAR PLANT UNIT 2 o 5 o o o31 6toFG4

"'EPETITIVE VIOLATION .OF ESF INSTRUMENTATION LIMITING CONDITIONS FOR OPERATION TOLERANCES DUE TO HIGHLY RESTRICTIVE ALLOWABLE VALUES EVENT DATE (5( LER NUMBER (5) REPORT DATE (7) OTHER FACILITIKS INVOLVED IB)

MONTH OAY YEAR gg'SOUSNTIAL ccc RSV~ OAY YEAR FACILITYNAMES DOCKET NUMBER(BI YEAR NUMBER NUMBER MONTH D. C. COOK UNIT 1 0 5 0 0 0 3 1 5 8 8 8 8 0 0 3 00 041 188 0 5 0 0 0 THIS REPORT IS SUBMITTED PURSUANT T0 THE AECUIREMKNTB oF 10 cFR (I: Icnecfr one or more of tne folloefrnFI (11 OPERATINO MODE (5) 20A02((r) 20.e05(cl 50.73(el(2) (lr) 73.71OI)

POWER 20.405( ~ ) (I ) (0 (I )

50.35(clHEI(S) 50.73(e)(2)(c) 73.71(cl (101 0 8 0 20A054 I (1)(S I 50.35(c)(2) 50.734) (2) (Till)(S)

(Till DTHER (Specify In Aortrect trerow emf In Text, NRC Form 20 e05( ~ l(1)(IQ) X 50,734) (2((O 50.734)(2)(TIIII(A) BBQI 20A054) (I ) (Ir) 50 73(e 50.73(el(2) 20.4054( IlI (r) 50.734)(2I(IS) 50.73(eN2)(xl LICENSEE CONTACT FOR THIS LER (12)

""" T. P. BEILMAN TELEPHONE NVMBEA AREA CODE INSTRUMENTATION AND CONTROL DEPARTMENT SUPERINTENDENT COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPOAT (13(

6 164 5-5 90'1 N):':"~'>g CAUSE SYSTEM COMPONENT MANUFAC.

TVAER EPOATABLE TO NPRDS SIN CAUSE SYSTEM COMPONENT MANUFAC.

TUAEA EPOATABL TO NPADS

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5%%(i eM53( (%5 SUPPLEMENTAL AEPORT EXPECTED I(el MONTH DAY YEAR EXPECTED SUBMISSION DATE 05)

YES lllyer, complete EXPECTED SUBMISSION OA TEI X NO ABSTRACT ILlmlt to ICOO tpecee, I A, epproxlmetely fifteen rlnele.rpcce typewnrten lintel (15)

On March ll, 1988 an equipment trend investigation was being performed on 4KV Bus Loss of Voltage relays and the 4KV Bus Degraded Voltage relays (EIIS/EK-27). The 'as found'ondition of these relays during past calibra-tion checks has generally been found to be beyond the Technical Specification (T.S.) allowable values. Each relay was adjusted to within allowable values at the time it was discovered out of specification. All relays were func-tional and would have performed the ESF function, although at a slightly different voltage than specified in T.S.

A survey of other plants and relay manufacturers indicate that our relays are functioning consistent with the manufacturer's specifications and that our T.S; allowable values are too restrictive for this type of function and the relay being used. We have not been able to locate replacement relays with the required setpoint sensitivity in the industry.

An engineering review is in progress to evaluate the maximum allowable voltage tolerances for the two applications. A Technical Specification change request will be submitted as soon as this evaluation has been com-pleted. In the interim, we will increase the calibration frequency from every eighteen months to monthly.

8804210251 38041k PDR ADOCK 05000316 DCD NAC Form 355 rn 41 ~

RC fonII 358A U.S NUCLEAR REGULATORY COMMISSION (983)

LICENSEE EIT REPORT (LER) TEXT CONTINVAQN APPROVED OMB NO. 3150-0104 EXPIRES I 8/31/88 fACILITYNAME l11 OOCKET NUMBER l2I LER NUMBER (8) PAGE (3(

YEAR SEGVENTIAL REVISION NVMSER NVMSEII D. C. COOK NUCLEAR PLANT UNIT 2 0 5 0 0 0 3 1 6 8 8 003 00 02 OF 0 TEXT /xmas NMcs /4/sSVEsIE s44 44UESna/ HRC fsmI 3554'4/ I IT(

Conditions Prior To Occurrence Unit 1 and Unit 2 were operating at 90 percent and 80 percent reactor thermal power, respectively, throughout the event. There were no inoperative structures, components, or systems that contributed to this event.

Descri tion of Event On March ll, 1988, an equipment trend investigation was being .performed on the 4KV Bus Loss of Voltage relays (EIIS/EK-27) and the 4KV Bus Degraded Voltage relays (EIIS/EK-27).. The setpoints for these relays have been found to be outside of the Technical Specification (T.S.) allowable values (T.S. 3.3.2;1-Table 3.3-4, items 8a and 8b). Of 144 individual calibrations

~

on the loss o'voltage relays over a seven year period, 68 were found to be outside of the T.S. tolerances. Of the 66 individual calibrations performed on the degraded voltage relays over a seven year period, 41 were found to be outside of the T.S. tolerances. The amount of deviation from the allowable setpoint band was limited and'distribution among the relays was random, indicating no particular relay to be.,defective. A survey of other utilities which use this type of relay revealed 'th'at the performance of our relays is consistent with their experience and within manufacturer's specifications. Each relay was readjusted to within allowable values at the time it was discovered out of specification.

The Loss of Voltage relays are installed to sense a loss of offsite or normal auxiliary power to the ESS 4KV buses. Once the loss of voltage has been sensed and after a two-second time delay, these relays in a 2/3 phases logic initiate load shedding and emergency diesel generator starting.

The Degraded Bus Voltage relays are installed to sense degraded reserve power feed to the ESS 4KV buses and, on a 2/3 phases logic with a two-minute time delay, trip open the reserve feed breakers and start the emergency diesel generators. Once the emergency diesel generator has restored bus voltage to .normal, safety loads are sequenced on to the safety buses. The Technical Specifications for Unit 1 and 2 have existing setpoints of 80 percent (+.5X, -1.0X) for the Loss of Voltage and 90 percent (+1.0/., -.5X) for the Degraded Grid detection. The tolerance on these wetpoints are closer than the relays can obtain, and more importantly, closer than required for performing their 'intended function, i.e., sensing loss of normal voltage, initiating load shedding, and diesel starting.

Cause Of The Event Calibration history shows a performance record in line with undervoltage relays used at other plants. We have reviewed the application of undervoltage relays for this function with other utilities and various relay manufacturers.

NRC EORM ESSA ~ U S GPO:(988 O824 538/455

~ CVO I

M NRC Form 3SBA U.S. NUCLEAR REGULATORY COMMISSION

($ 83)

LICENSEE E T REPORT (LER) TEXT CONTINUA APPROVEO OMB NOi 3(50&lei EXPIRES: 8/3I/88 SAC(LITT NAME (Il COCKET NUMBER (ll LER NUMBER (el PACE (3)

YSAII M~E SSCVSNT/AL Qiq REVISION NVMSSR ~~ NVMSSR D. C. COOK NUCLEAR PLANT UNIT 2 0 5 0 0 0 3 1 8 8 0 0 3 0 0 0 30F 0 4 Tm(T /Pmep NMRp i/npuied, vm aSNone/NRC An/I 4548/ (Ill We have concluded that the undervoltage relays are being properly applied in this mode as a conventional protective relay. This use would not normally involve having an acceptance band. Many utilities consulted had no Technical Specification required tolerances for this function and others had broader allowance values which more closely reflect the manufacturer's expected performance tolerances.

Anal sis Of The Event American Electric Power's System voltage studies have been performed and indicate that the worst case voltage on the ESS buses at the the Cook Nuclear Plant would be 87.3 percent. We do not expect the ESS bus voltage to drop to a lower voltage than this unless a complete plant blackout condition occurred. Under a blackout condition, the ESS bus voltage would quickly drop well below the 80 percent undervoltage relay setpoint load shedding and diesel start. The only function of the 80 and'nitiate percent voltage relays is to sense a total loss of ESS bus voltage.

Therefore, the setpoint deviations we'e experienced translat;e into a different line voltage and time than the Technicak. S~oitication"calls for, but the time involved for this additional voltage drop is insignificant.

The function of the degraded bus relays are to disconnect the plant from the grid for a sustained degraded condition, i.e., less than 90 percent voltage for at least two minutes. They are armed only when the plant is fed from offsite power. Plant normal configuration is to be fed from the generator auxiliary transformers except for short periods during startup and shutdown. Therefore, these relays are not normally active during unit operation.

Again, relating to our system studies, we do not believe the slight out of tolerance to be a safety problem for the degraded bus relays. Our studies indicate that the lowest possible offsite voltage to our buses would be 93.3 percent except for the short period during Reactor Coolant Pump (RCP) starting, which is less than one minute. During RCP starting, the bus voltage can dip to 87.3 percent, however, we are protected from an unnecessary trip by the two-minute time delay on this circuit.

Based on the above, it has been concluded that there is no Jeopardy to the health and safety of the public as a result of this event.

N Rc poRM SSBA *U.S.GPO, IBBe.o e2i 538/i55 IA 4'll

NRC Form 3SSA US. NUCLEAR REGULATORY COMMISSION (BB31 LICENSEE IehlT. REPORT (LER) TEXT CONTINU/(IN APPROVED OMB NO. 3150-0(04 EXPIRES: 8/31/88 ACIUTY NAME (11 DOCKET NUMBER (2( LER NUMBER (8( PAGE (3)

SECUENTIAL REVISION D. C. COOK NUCLEAR PLANT UNIT 2 YEAR NUMBER yg NUMBER o s o o o 8 8 0 0 3 00 04 OF 0 4 TEXT /B'I/RES gad /E /dykey INS //I/ddd/HRC Fenn 38543/ (171 Corrective Action Equivalent relays with less drift have not been identified as available in the industry. The relays were recqlibrated to within the allowable values at the time of discovery during the calibration. In addition, all of the relays were recalibrated from April 7-9, 1988. Out of the 36 relays for Units 1 and 2, eleven were found out of specification. Unit 1's were last calibrated in July 1987 and Unit 2's were calibrated in February 1988. An engineering review is in progress to evaluate acceptable Technical Specifi-cation values and tolerances for the type. of relay used. A Technical Specification change request will be submitted as soon as this evaluation has been completed. In the interim, we will increase the calibration frequency from every eighteen months to monthly until the trend indicates a different frequency is )ustified.

Failed Com onent Identification None.

Previous Similar Events LER 316/81-015 LER 315/81-017 LER 315/82-051 LER 315/82-059 LER '316/82-100 LER 316/82-108 LER 315/83-069 LER 315/83-094 NRC FOAM ESSA ' U.S.GPO:1888.0.824 538/F55 l1

indiana Michigan Power Company Cook Nuclear Plant P.O. Box 458

~

Bridgrnan, Ml 49106 616 465 5901 Z

INQMNA MCHSG@N POWER April ll, 1988 United States Nuclear Regulatory Commission Document Control Desk Washington, D.C. 20555 Operating License DPR-58 Docket No. 50-316 Document Control Manager:

In accordance with the criteria established by 10 CFR 50.73 entitled Licensee Event Re ortin S stem, the following report is being submitted:

88-003-00 Sincerely, W. G. Smith, Jr.

Plant Manager WGS:clw Attachment cc: D. H. Williams, Jr.

A. B.

M. P.

Davis, Region Alexich III R. F. Kroeger H. B. Brugger R. W. Jurgensen NRC Resident Inspector J. F. Stang, NRC R. C. Callen G. Charnoff, Esq.

Dottie Sherman, ANI Library D. Hahn INPO PNSRC A. A. Blind P. A. Barrett/P. Lauzau